Small changes by businesses and consumers can make a big difference in saving the lives of animals worldwide, said Wayne Pacelle, chief executive of the Humane Society of the United States.
"If we just reduce our meat consumption by 15 percent, we'd save a billion animals," he told CNBC's "Squawk Box" on Wednesday.
"It's an incremental process of enlightening people. There's so many issues ... animals raised for food, there's testing, there's wildlife management issues, the Cecil issue — the trophy hunting, there's dog fighting, there's cock fighting. I mean everything under the sun," he said.
The Cecil issue refers to the prized African lion whose death at the hands of an American hunter last year sparked international outrage. Walter Palmer, a 55-year-old dentist from Minnesota, allegedly paid $50,000 to hunt the animal.
There's a bigger business in people willing to pay to see magnificent animals, Pacelle said. "You can watch an elephant 100 times. You can shoot the elephant only once."
Pacelle, author of the new book "The Humane Economy," said: "We're starting to recognize as a society that animals do feel, they do think, they have their own lives that matter to them."
Pacelle singled out Wal-Mart as a positive force for change in the way animals who provide food are treated. "Wal-Mart sells 25 percent of groceries in the United States, an incredible volume of food. Wal-Mart now says they're going to procure all of [its] eggs from operations that don't confine the hens in small cages."
In his book, Pacelle also talked about how technology plays a part in reducing the need for animals as food. "We're creating plant-based proteins that make meat-like substances, that have the taste and texture of meat, but it's all plant-based."